Robby Vroemans
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[ASAP] Steric Effects on the Oxygen Reduction Reaction with Cobalt Porphyrin Atropisomers
[ASAP] Chemoselective Diazine Dearomatization: The Catalytic Enantioselective Dearomatization of Pyrazine
[ASAP] Constructing Novel Biobased Phosphorus-Containing Oligomeric Lactates toward Synchronously Enhancing the Toughness and Fire Safety of Poly(lactic acid)
[ASAP] Lessons Learned─Splashing Incidents of Methanol and ortho-Chlorobenzaldehyde into Eyes and Faces Due to Accidental Detachment of Luer Slip Syringes and Needles
Synthetic Chemistry in Flow: From Photolysis & Homogeneous Photocatalysis to Heterogeneous Photocatalysis
Flow systems are considered as a promising solution for practical applications of light-driven reactions. Design and optimization of the reaction devices based on the characteristics of reaction types is important to achieve a full utilization of incident light and active sites of the photocatalysts, thereby achieving amplification of photocatalytic reactions.
Abstract
Photocatalytic synthesis of value-added chemicals has gained increasing attention in recent years owing to its versatility in driving many important reactions under ambient conditions. Selective hydrogenation, oxidation, coupling, and halogenation with a high conversion of the reactants have been realized using designed photocatalysts in batch reactors with small volumes at a laboratory scale; however, scaling-up remains a critical challenge due to inefficient utilization of incident light and active sites of the photocatalysts, resulting in poor catalytic performance that hinders its practical applications. Flow systems are considered one of the solutions for practical applications of light-driven reactions and have experienced great success in photolytic and homogeneous photocatalysis, yet their applications in heterogeneous photocatalysis are still under development. In this perspective, we have summarized recent progress in photolytic and photocatalytic synthetic chemistry performed in flow systems from the view of reactor design with a special focus on heterogeneous photocatalysis. The advantages and limitations of different flow systems, as well as some practical considerations of design strategies are discussed.
Discovery of selective monosaccharide receptors via Dynamic Combinatorial Chemistry
DOI: 10.1039/D4OB00015C, Communication
The molecular recognition of saccharides by synthetic hosts has become an appealing but elusive task in the last decades. Herein, we combine Dynamic Combinatorial Chemistry (DCC) for the rapid self-assembly...
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Advances in the Homogeneously Catalyzed Hydrogen Production from Biomass Derived Feedstocks: a Review.
Biomass-derived feedstocks for hydrogen production are crucial as an alternative to fossil fuel especially in those areas where green electricity and clean water are scarce. In this framework the transformation of simple (formic acid, alcohols) and more complex (polyalcohols, sugars and cellulose) bio-derivatives in pure hydrogen is recognized as a promising approach. Parallel to great effort in heterogeneous catalysis, milder molecular systems represent a more selective eye for alternative solutions and mechanistic insights. In the present review the introduction summarizes the challenges in the catalytic utilization of biomass-derived feedstocks, followed by the advances in homogeneously catalyzed hydrogen production from different substrates which will cover formic acid, with oustanding efficiency with noble metals and promising results with earth abundant ones and alcohols and polyalcohols, with particular emphasis to the development of heterogenized systems, ligand assisted catalysts and bi-catalytic synergistic solutions which allow to avoid base and to promote catalyst stability and recyclability. In the last part, description of hydrogen production from more complex substrates, such as sugars and cellulose, will show the role of molecular complexes in main and side reactions. Critical comments on the reported advances are provided along the whole discussion.
[ASAP] Nucleophilic Aromatic Substitution (SNAr) as an Approach to Challenging Nitrogen-Bridged BODIPY Oligomers
[ASAP] A Flow Chemistry Platform for Photochemical Macrocyclization of Peptides
[ASAP] Dual Acridine/Decatungstate Photocatalysis for the Decarboxylative Radical Addition of Carboxylic Acids to Azomethines
[ASAP] Exposure of Peregrine Falcons to Halogenated Flame Retardants: A 30 Year Retrospective Biomonitoring Study across North America
Rapid Cyclic Acetal and Cyclic Ketal Synthesis Assisted by a Rotary Evaporator
Synlett
DOI: 10.1055/a-2293-3243
Herein, we present a rapid and efficient method for synthesizing cyclic acetals and ketals utilizing a rotary evaporator. Unlike the conventional Dean–Stark dehydration process, which typically demands extended reaction times and copious amounts of organic solvents, our approach affords the synthesis of cyclic acetals and ketals with varying ring sizes in 30 min while using minimal quantities of dimethyl sulfoxide as the solvent. This innovative protocol features high yields, fast reactions, easy operation, and broad substrate applicability.
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Georg Thieme Verlag KG Rüdigerstraße 14, 70469 Stuttgart, Germany
Article in Thieme eJournals:
Table of contents | Abstract | Full text
Catalysts, Vol. 14, Pages 250: Diphenyl Carbonate: Recent Progress on Its Catalytic Synthesis by Transesterification
Catalysts, Vol. 14, Pages 250: Diphenyl Carbonate: Recent Progress on Its Catalytic Synthesis by Transesterification
Catalysts doi: 10.3390/catal14040250
Authors: Dong Wang Feng Shi Guochao Yang
Diphenyl carbonate is one of the raw materials used for the synthesis of polycarbonate, and its green and clean production is of great importance to the non-phosgene process for polycarbonate. The production of diphenyl carbonate by transesterification is its representative process route and is considered to be one of the typical examples of a green and sustainable process for chemicals. Since the discovery of the transesterification catalyst for diphenyl carbonate in the 1970s, researchers have been committed to improving its catalytic activity and selectivity and, correspondingly, the reaction engineering process. However, thermodynamic limitations, low activity, low selectivity, and limited stability have been bottlenecks that the transesterification catalyst has not been able to completely overcome, and the improvement of the catalyst is still ongoing. Therefore, this review takes the transesterification reaction of dimethyl carbonate and phenol as a model reaction and, based on a review of the progress in catalyst research on catalytic reaction processes, tries to clarify the structure–activity relationship between catalytic active sites and catalytic performance in homogeneous and heterogeneous catalytic processes and provides an overview of the progress in catalyst synthesis and modification.
[ASAP] Ligand-Bound CO2 as a Nonclassical Route toward Efficient Photocatalytic CO2 Reduction with a Ni N-Confused Porphyrin
[ASAP] Mild Method for Deprotection of the N-Benzyloxycarbonyl (N-Cbz) Group by the Combination of AlCl3 and HFIP
Multicomponent synthesis via acceptorless alcohol dehydrogenation: an easy access to tri-substituted pyridines
DOI: 10.1039/D4RA00439F, Paper
The multicomponent synthesis of 2,4,6-trisubstituted pyridine via acceptorless alcohol dehydrogenation using ammonium acetate as a nitrogen source catalyzed by hydroxyapatite-supported palladium nanoparticles as a heterogeneous catalyst.
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Bridging the information gap in organic chemical reactions
Nature Chemistry, Published online: 28 March 2024; doi:10.1038/s41557-024-01470-8
Lack of standardization, transparency and interaction creates information gaps in scientific publications. Through strategies such as voluntary information management, standardization of reaction set-ups, and smart screening approaches, this Perspective gives guidelines on how to improve data management in publications reporting chemical reactions, focusing on reproducibility, standardization and evaluation of synthetic transformations.[ASAP] Oxygen-Dependent Ligand-Controlled Iron-Catalyzed Chemoselective Synthesis of Olefins and Vinyl Nitriles
[ASAP] Discovering Novel Organophosphorus Compounds in Wastewater Treatment Plant Effluents through Suspect Screening and Nontarget Analysis
[ASAP] One-Pot Microbial Cell Factory Strategy for the Production of Protocatechuic Acid from Polyethylene Terephthalate Waste
[ASAP] Dispersion Control over Molecule Cohesion: Exploiting and Dissecting the Tipping Power of Aromatic Rings
Robby VroemansDillon, you son of a b*tch!
[ASAP] Scalable Synthesis of All Stereoisomers of 2-Aminocyclopentanecarboxylic Acid─A Toolbox for Peptide Foldamer Chemistry
Characterization of polymer properties and identification of additives in commercially available research plastics
DOI: 10.1039/D4GC00659C, Paper
This work reports the analysis of 59 commercially available polymers from 20 different polymer classes for thermal properties, macrostructure, molecular mass distribution, and inorganic and organic additives, highlighting the need to characterize research polymers prior to recycling studies.
To cite this article before page numbers are assigned, use the DOI form of citation above.
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[ASAP] Strongly Polarized π-Extended 1,4-Dihydropyrrolo[3,2-b]pyrroles Fused with Tetrazolo[1,5-a]quinolines
Synthesis goes uphill
Nature Synthesis, Published online: 27 March 2024; doi:10.1038/s44160-024-00515-7
Coupling an exergonic process with an orthogonal, endergonic one has opened the door to drive artificial systems away from equilibrium. Now, this concept is used to bias the outcome of an uphill chemical reaction.Electrochemical Dehydration of Dicarboxylic Acids to Their Cyclic Anhydrides
An intramolecular electrochemical dehydration reaction of dicarboxylic acids to their cyclic anhydrides is presented. This electrolysis allows dicarboxylic acids as naturally abundant, inexpensive, safe, and readily available starting materials to be transformed into carboxylic anhydrides under mild reaction conditions. No conventional dehydration reagent is required. The obtained cyclic anhydrides are highly valuable reagents in organic synthesis, and in this report, we use them in-situ for acylation reactions of amines to synthesize amides. This work is part of the recent progress in electrochemical dehydration, which – in contrast to electrochemical dehydrogenative reactions for example – is an underexplored field of research. The reaction mechanism was investigated by 18O isotope labelling, revealing the formation of sulfate by electrochemical oxidation and hydrolysis of the thiocyanate supporting electrolyte. This transformation is not a classical Kolbe-electrolysis, because it is non-decarboxylative, and all carbon atoms of the carboxylic acid starting material are contained in the carboxylic anhydride. In total, 20 examples are shown with NMR yields up to 71%.
Photocatalysts for steering charge transfer and radical reactions in biorefineries
Nature Synthesis, Published online: 26 March 2024; doi:10.1038/s44160-024-00499-4
Synthesis of fuels and chemicals from renewable biomass is an important way to achieve sustainable development. This Review summarizes catalyst design for steering interfacial charge transfer and radical intermediate reactions in photocatalytic biorefineries.[ASAP] Cesium Carbonate Promoted Direct Amidation of Unactivated Esters with Amino Alcohol Derivatives
Photocatalytic efficient cleavage of C-C bond in lignin model using water as solvent
Publication date: 15 April 2024
Source: Molecular Catalysis, Volume 559
Author(s): Jie Xu, Qiqi Li, Tianlin Ma, Yujie Wang
Pillararene-inspired arenes: Synthesis, properties and applications compared to the parent macrocycle
Publication date: 15 June 2024
Source: Coordination Chemistry Reviews, Volume 509
Author(s): Sem Bleus, Wim Dehaen